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authorzhenggy <zhenggy@chinatelecom.cn>2021-09-14 09:51:15 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-09-22 12:26:42 +0200
commit9ebbb8b964f5201d901b26741046ea1505320bf3 (patch)
tree096c41c641c5c6f296ec09563d0568a62126f539
parentbaf450477143360570bf6581c226912da2862f54 (diff)
tcp: fix tp->undo_retrans accounting in tcp_sacktag_one()
commit 4f884f3962767877d7aabbc1ec124d2c307a4257 upstream. Commit 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time") may directly retrans a multiple segments TSO/GSO packet without split, Since this commit, we can no longer assume that a retransmitted packet is a single segment. This patch fixes the tp->undo_retrans accounting in tcp_sacktag_one() that use the actual segments(pcount) of the retransmitted packet. Before that commit (10d3be569243), the assumption underlying the tp->undo_retrans-- seems correct. Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time") Signed-off-by: zhenggy <zhenggy@chinatelecom.cn> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ipv4/tcp_input.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a1768ded2d54..c0fcfa296468 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1209,7 +1209,7 @@ static u8 tcp_sacktag_one(struct sock *sk,
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (tp->undo_marker && tp->undo_retrans > 0 &&
after(end_seq, tp->undo_marker))
- tp->undo_retrans--;
+ tp->undo_retrans = max_t(int, 0, tp->undo_retrans - pcount);
if ((sacked & TCPCB_SACKED_ACKED) &&
before(start_seq, state->reord))
state->reord = start_seq;